Cathode ray oscillograph



June'I 12, 1934.l

H. w. PARKER 1,962,873

cA'rHoDE RAY VoscILI..0GRA PH Filed Aug. 411, 193s E :El- :L

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y ATTORNEY Patented -June '12, 1934 CATHODE RAY OSCILLO GRAPH Henry W.Parker, Toronto, Ontario, Canada, as-

signor to Rogers Radio Tubes, Limited, Toronto, Ontario, Canada, acorporation o f Ontario,

Canada.

Application August 11, 1933, serial No. 684,657 3 claims. (ci. 17.1-95)My invention pertains to oscillographs' and relates in particular tothat type of such devices as are known as Braun tube or cathoderayoscillographs. l

5 Anobject of my invention comprises producing a simplified andeffective cathode ray oscillograph.

Another object. comprises producing a cathode ray oscillograph in whichdistortion of the porl trayed wave is eliminated. v

A further object comprises producing an oscillograph in which thenecessity for complicated linear time mechanisms is eliminated.

A still further object comprises producing an l oscillogaph in which avoltage wave may be portrayed in cylindrical coordinates in a closedcon.- tinuous manner on a surface adapted to be vieweclsimultaneously bya number of observers.

A still further objectcomprises producing an,

oscillograph in which the time axis extends linearly and continuouslyaround a cylinder or on a spherical vsurface to eliminate the distortionpresent in oscillographs as now used.

I accomplish the above and other novel and f desirable features whichwill I'hereinafter be pointed out and described by providing a novelform of cathode ray oscillograph in which an electron stream is causedto trace a voltage wave in cylindrical or spherical coordinatescontinuously and in closed configuration upon a iiuorescent coatingapplied to the walls of a cathode ray tube.

In'the drawing accompanying and forming a part of this specification,Fig. 1 illustrates dia-,l

grammatically one embodiment of my' cathode ray oscillograph showing thecircuit diagram for operating the same. y

Fig. 2 is a partly sectioned, broken view of the -same showing thepreferred disposition .of the coils for rotating the electron stream.

Referring now to the drawing, there is provdedsa partially exhaustedvitreous envelope which is preferably constructed of glass, formed asshown in Fig. 1 with a portion thereof in the form of a cylinder ofuniform diameter, the end 3 of which is closed andv is in theform of aspherical section. The cylindrical portion and the end portion arecoated with a coating 2 vof zinc sulphide or other well known materialwhich fluoresces upon bombardment by electrons. The envelope preferablycontains mercury vapor.

There is provided within the envelope 1 a cathode 11 which may be anywell known source ofA electrons either direct or indirectly heated, afocussing cylinder 10 and the usual perforated anode 9 with connectionstherefor respectively to the usual contact prongs 13 maintained in aninsulating base 12 attached to the envelope 1.

The radius of the spherical section 3 of the envelope is approximatelyequal to the distance from the end of the tube to the anode 9 and incommercial embodiments which have been constructed and successfullyoperated, this distance is approximatelyl12".

There is provided a series of inductance coils or electromagnets 4, 5,7, and 8 which are positioned at right angles to each other about theneck of the envelope 1 as shown in Fig.' 2 and connected in the/form ofa bridge. Inductances 4 and 8 are connected in series and to a source ofmternating current, while inductances 5 and 7 are connected in seriesthrough a condenser 6 and across the source of alternating currentsupply. This arrangement provides a well known method o f splittingasingle phase alternating current intoy two phase, thereby obtaining atwo phase rotating magnetic eld which is utilized electromagneticallythrough the inductance coils or electromagnets`4, 5, 7 and 3 to rotatethe electron stream within the envelope'l. A i

Direct current operating potentials are supplied tov the filament 11,vfocussing cylinder l0 and anode 9 from a rectifier connected to thealternating current source as shown in Fig. 1 and provided with a`potentiometer 15 from which tively the operating potentials andcurrents to the cathode, focussing cylinder, Iand anode. The signal tobe portrayed is impressed upon the anode 9 through transformer 14 asshown. The direct current potential applied to the anode is adjusted bypotentiometer tap 21 to a value sufficient to cause the electron stream17 to impinge upon a desired portion of the coating 2 on the envelope 1.By varying the anode voltage the uorescent spotmay be placedupon anydesired portion of the coating and as the beam is rotated by theinductances 4, 5, 7, and 8, a luminous line or linear time axis is drawncontinuously around the cylindrical portion of envelope 1 in closedconfiguration or in closed conguration on the spherical portion 3. Theradius of curvature of the beam 17 is a function of the velocity of theelectron stream, if the eld supplied by inductances 4, 5, 7, and 8 issteady, hence 105 a low velocity stream will be directed to the lowerportion of the fluorescent cylinder and a high velocity stream to theupper portion of the cylinder or to the spherical portion. Varyingpotentials of the voltage wave of the signal to be 110 -taps 19, 20 and21 are taken to supply respecportrayed vary the instantaneous velocityof the stream 17 to vary the instantaneous position of the linear time-axis produced by the rotating beam to portray in cylindrical orspherical coordinates in a continuous closed conguration a voltage waveupon the fluorescent material 2.

The inductances 4, 5, 7, and 8 are preferably located at right angles toeach other and as shown in Fig. 2. These inductances may be as shown aircored, or they may be provided if desired with laminated cores. Thesplit phase beam rotating mechanism being external of the envelope 1,may be easily adjusted with respect to the beam and also With respect tothe inner-relation of the inductanccs to provide the optimum rotation ofthe beam. Obviously, if the velocity of the electron stream isincreased, the voltage Wave may' be portrayed in closed circularconfiguration and wholly in spherical coordinates upon the sphericalportion 3 of the envelope 1, or, if desired, the Voltage wave may beportrayed partially on the cylindrical Walls of the envelope 1 and onthe spherical portion 3 in combined cylindrical and sphericalcoordinates, respectively.

From the foregoing it will be readily observedthat my novel cathode rayoscillograph provides means for demonstrating the'actual Wave form ofvariable electromotive forces to groups of observers and therefore is ofvaluev for demonstration purposes in universities and colleges. It isalso evident that it is a convenient laboratory apparatus which willallow photographs to be made of a voltage Wave by simply Wrapping thenegative around the cylindrical portion of the envelope to obtain anoscillogram without distortion in true rectilinear coordinates onalinear time axis. Many other uses will readily occur to those skilledin the art. The manufacturing possibilities of the tube for my improvedoscillograph are unique on account of the simplicity of construction,there being included in the tube no delecting plates.

While I have thus completely described one embodiment of my device', itwill be readily apparent' that numerous changes may be made thereinwithout departing from the spirit or narrowing the Scope of myinvention.

Having thus described my invention, what I claim as new and original anddesire to obtain by United States Letters Patent is as follows:

1. A cathode ray oscillograph comprising, a vitreous envelope, a portionof the walls of which are in the form of a cylinder of substantiallyuniform diameter, a coatingof material rendered luminous on bombardmentby electrons on the inner Walls oi' said cylindrical portion, means forproducing a stream of electrons Within said envelope, means for causingsaid stream of electrons to rotate to trace a continuous coordinate lineon said coating and means for varying the velocity of said stream totrace a second-coordinate line on said coating whereby a voltage Wavemay be portrayed in cylindrical coordinates on the cylindrical portionof said envelope.

2. A cathode ray oscillograph comprising, a vitreous envelope, aconsiderable portion of the walls of which are in the form of a cylinderof substantially uniform diameter, a coating of -iiuorescent material onthe inner walls of said cylindrical portion, means for producing astream of electrons within said envelope, means for causing said streamof electrons to rotate to trace a continuous coordinate line on thecoating of said envelope and means for varying the instantaneousposition of said line in accordance with instan taneous values of thevoltage of an applied varyling voltage to display in closedconfiguration on said coating a voltage wave in cylindrical coordinates.

3. A cathode ray oscillograph comprising, a vitreous envelope, a portionof the walls of which` are in the form of a cylinder of uniform diameter, a coating of fluorescent material on the inner walls of saidcylindrical portion, means for producing a stream of electrons Withinsaid envelope, means including a source of alternating current ofsubstantially. constant voltage and frequency for rotating said streamof electrons to trace a continuous closed line on said coating and meansincluding a source of varying po- L tential for varying thevelocity ofsaid stream to vary the instantaneous position of said line inaccordance with the instantaneous values of. the voltage ofsaid varyingsource to continuously portray a voltage Wave in cylindrical coordinatesand in closed configuration on said coating.

HENRY W. PARKER.

